The invention relates to a coupling device for cassette tape recorders, and more particularly to a coupling device for coupling a compact cassette tape recorder with a radio set or an accessory unit such as a tuner, a microphone pre-amplifier to provide an integrally joined assembly.
The prior art practice of coupling a tape recorder with a radio set has been by an electrical cord. However, such coupling represents a time and labor consuming operation, the coupled assembly has been disorderly and the connection is unsightly and is not susceptible to portable use.
With the advent of tape cassettes, a cassette tape recorder for use therewith has been constructed and advances in technology have resulted in tape cassettes of increasingly smaller size. In particular, a miniature cassette tape recorder, which is intended for use with a micro-cassette of a size comparable to a packet of matches and which has been developed by the present applicant, is constructed in a size which can be received in the pocket of a suit or shirt. The use of an electrical cord or the like to couple such a miniature cassette tape recorder with a radio set or other electroacoustic instrument would be unfavorable, and it is desirable to provide a coupling device which mechanically connects both units while providing an electrical connection therebetween. However, in the construction of such a coupling device, the electrical contacts provided on either instrument are externally exposed, particularly when a pin and socket connection is employed, and it is necessary to avoid a poor electrical connection which may be caused as by the ingress of dust, dirt or the like into the socket opening. Thus it is seen that some means be desirably provided to close the socket opening when the recorder is not coupled with another electroacoustic instrument.
On the other hand, the application of a miniature cassette tape recorder could be extended by allowing an accessory such as a tuner, a microphone pre-amplifier or the like to be coupled therewith in a simple manner. Specifically, every tape recorder is provided with a magnetic head, an amplifier and a loudspeaker, so that an output signal from a tuner may be amplified to drive the loudspeaker of the recorder, thus enabling the recorder to be used as a radio set. When the recorder is in its record mode, a mixed recording can be achieved for an output signal from a tuner and an input signal from its internally housed microphone. Additionally, if a microphone pre-amplifier is coupled with a recorder, high quality recording can be accomplished by using an external microphone.
To enable the miniature cassette tape recorder to be used in a variety of applications, it is highly desirable that the associated accessory can be easily coupled with the tape recorder. It is also desirable that the electrical circuit within the recorder can be fully utilized when it is coupled with another instrument. By way of example, it is desirable that the connection with the tape recorder be such that when a tuner is coupled therewith, a power source contained within the recorder may feed power to the tuner while when the recorder is operated as a radio set, the microphone internally housed within the recorder is disabled.